MVVM: ¿hay una clase base de modelo de vista de código abierto?

Question

Estoy trabajando con MVVM y en lugar de reinventar la rueda, pensé que podría encontrar una clase base de modelo de vista de código abierto. No puedo encontrar uno

Answer 1

Microsoft Prism. Acceso completo al código fuente Una curva de aprendizaje algo empinada, pero una vez que lo manejas, funciona muy bien.

Answer 2

Sugeriría que los principios básicos de MVVM son tan simples que sería más fácil reinventar la rueda. Toda la funcionalidad básica que necesita es que la clase implemente INotifyPropertyChanged (la clase base podría tener la implementación de estilo estándar de OnPropertyChanged(string propertyName)). Más allá de eso está el RelayCommand o similar, solo una implementación ICommand que ejecuta un delegado en Execute.

Todo en todos, unas pocas líneas de código, y lo mantiene muy limpio. ¿Qué otra funcionalidad estás buscando? Si se trata de BDO subyacente (digamos DataRow, XmlNode o POCO), entonces no debería estar realmente en la clase base de VM, sino en una clase derivada.

Espero que ayude.

Answer 3

Mira el blog de Nikhail Kothari para su biblioteca SilverlightFX, es un MVVM de código abierto que puede serle útil.

Answer 4

MVVM Light también es una buena solución, y tiene un muy fácil de encontrar clase base :-)

Answer 5

Aquí es un ejemplo de la mía ... no lo puedo realmente te ayuda, porque quiero Quiero que mis ViewModels a Do será diferente de lo que quieres que hagan tus modelos de vista ... pero quizás te sirva de inicio. Y la cosa con la clase base es si usted se pega en su Core ... solo tiene que escribir una vez ...

Imports System.ComponentModel 
Imports System.Windows 
Imports Microsoft.Practices.Composite.Events 
Imports WavelengthIS.Core.Services 
Imports WavelengthIS.Core.Bases 
Imports Ocean.OceanFramework.CommonDialog 
Imports WavelengthIS.WPF.Events 

Namespace WavelengthIS.WPF.Bases 

    Public MustInherit Class ViewModelBase 
     Inherits WavelengthIS.Core.Bases.Base 
     Implements IDisposable, INotifyPropertyChanged 

#Region " Declarations " 
     Private _headerinfo As String 
     Private _backgroundworker As BackgroundWorker 

#End Region 

#Region " Properties " 
     Public Property HeaderInfo() As String 
      Get 
       Return _headerinfo 

      End Get 
      Set(ByVal value As String) 
       If Not (value Is String.Empty) Or Not (IsNothing(value)) Then 
        _headerinfo = value 
       End If 

      End Set 
     End Property 

     Protected ReadOnly Property BackGroundWorker() As BackgroundWorker 
      Get 
       If _backgroundworker Is Nothing Then 
        _backgroundworker = New BackgroundWorker 
       End If 
       Return _backgroundworker 
      End Get 
     End Property 

     Private _isdirty As Boolean = False 
     Protected Property IsDirty As Boolean 
      Get 
       Return _isdirty 
      End Get 
      Set(ByVal value As Boolean) 
       If Not Equals(value, _isdirty) Then 
        _isdirty = value 
        If _isdirty = True Then 
         DisableNavigation() 
        Else 
         EnableNavigation() 
        End If 
       End If 
      End Set 
     End Property 

     ''' <summary> 
     ''' not a databinding property. No need for onpropertychanged notifications 
     ''' </summary> 
     ''' <value></value> 
     ''' <returns></returns> 
     ''' <remarks></remarks> 
     Protected Property IsLoading As Boolean = False 

     Private _haschanges As Boolean 
     Public Property HasChanges As Boolean 
      Get 
       Return _haschanges 
      End Get 
      Set(ByVal value As Boolean) 
       If Not Equals(value, _haschanges) Then 
        _haschanges = value 
        If value = True Then 
         GetEvent(Of Events.DisableCloseButtonEvent).Publish(True) 
        End If 
        OnPropertyChanged("HasChanges") 
       End If 
      End Set 
     End Property 


#End Region 

#Region " Dialogs " 
     'This is not in Bases because it would cause circular references. 

     ''' <summary> 
     ''' Gets the IDialogService registered with the ServiceContainer. 
     ''' use ShowMessage or ShowException in child code. 
     ''' </summary> 
     Private ReadOnly Property Dialog() As Dialog.IDialogService 
      Get 
       Return GetService(Of Dialog.IDialogService)() 
      End Get 
     End Property 

     Protected Function ShowMessage(ByVal message As String, ByVal caption As String, ByVal button As Dialog.DialogButton, ByVal image As Dialog.DialogImage) As Ocean.OceanFramework.CommonDialog.CustomDialogResult 
      GetEvent(Of Events.DialogShowingEvent).Publish(True) 
      Dim rslt As CustomDialogResult = Dialog.ShowMessage(message, caption, button, image) 
      GetEvent(Of Events.DialogShowingEvent).Publish(False) 
      Return rslt 
     End Function 

     Protected Sub ShowException(ByVal message As String, Optional ByVal expandedMessage As String = Nothing, Optional ByVal image As Dialog.DialogImage = Core.Services.Dialog.DialogImage.Error) 
      GetEvent(Of Events.DialogShowingEvent).Publish(True) 
      Dialog.ShowException(message, expandedMessage, image) 
      GetEvent(Of Events.DialogShowingEvent).Publish(False) 

     End Sub 
#End Region 

#Region " Wait States " 

     Private ReadOnly Property Wait As WavelengthIS.Core.Services.IWaitingService 
      Get 
       Return GetService(Of IWaitingService)() 
      End Get 
     End Property 

     Protected Sub BeginWait() 
      GetEvent(Of Events.DisplayWaitingControlEvent).Publish(True) 
     End Sub 

     Protected Sub EndWait() 
      GetEvent(Of Events.DisplayWaitingControlEvent).Publish(False) 
     End Sub 
#End Region 

#Region " Events " 
     Public Event PropertyChanged(ByVal sender As Object, ByVal e As System.ComponentModel.PropertyChangedEventArgs) Implements System.ComponentModel.INotifyPropertyChanged.PropertyChanged 


#End Region 

#Region " Constructor " 
     Public Sub New() 
      _backgroundworker = New BackgroundWorker 
      AddHandler _backgroundworker.DoWork, AddressOf BackGroundWorker_DoWork 
      AddHandler _backgroundworker.RunWorkerCompleted, AddressOf BackGroundWorker_RunWorkerCompleted 

     End Sub 

#End Region 

#Region " IDisposable Support " 

     Private disposedValue As Boolean = False  ' To detect redundant calls 

     ' IDisposable 
     Protected Overridable Sub Dispose(ByVal disposing As Boolean) 
      If Not Me.disposedValue Then 
       If disposing Then 
        ' TODO: free other state (managed objects). 
       End If 

       ' TODO: free your own state (unmanaged objects). 
       ' TODO: set large fields to null. 
      End If 
      Me.disposedValue = True 
     End Sub 
     ' This code added by Visual Basic to correctly implement the disposable pattern. 
     Public Sub Dispose() Implements IDisposable.Dispose 
      ' Do not change this code. Put cleanup code in Dispose(ByVal disposing As Boolean) above. 
      Dispose(True) 
      GC.SuppressFinalize(Me) 
     End Sub 
#End Region 

#Region " Debugging Helpers " 
     <Conditional("DEBUG")> _ 
     Public Sub VerifyPropertyName(ByVal propertyName As String) 

      'If you raise PropertyChanged and do not specify a property name, 
      'all properties on the object are considered to be changed by the binding system. 
      If String.IsNullOrEmpty(propertyName) Then 
       Return 
      End If 

      ' Verify that the property name matches a real, 
      ' public, instance property on this object. 
      'If TypeDescriptor.GetProperties(Me)(propertyName) Is Nothing Then 
      ' Dim msg As String = "Invalid property name: " & propertyName 
      ' Throw New Exception(msg) 
      'End If 
     End Sub 

     Private _ThrowOnInvalidPropertyName As Boolean 
     Protected Property ThrowOnInvalidPropertyName() As Boolean 
      Get 
       Return _ThrowOnInvalidPropertyName 
      End Get 
      Private Set(ByVal value As Boolean) 
       _ThrowOnInvalidPropertyName = value 
      End Set 
     End Property 




#End Region 

#Region " INotifyProperty Changed Method " 


     Protected Overridable Sub OnPropertyChanged(ByVal strPropertyName As String) 
      Me.VerifyPropertyName(strPropertyName) 

      If Me.PropertyChangedEvent IsNot Nothing Then 
       RaiseEvent PropertyChanged(Me, New System.ComponentModel.PropertyChangedEventArgs(strPropertyName)) 
      End If 


     End Sub 

     Private Function QualifyString(ByVal str As String) As Boolean 



      Return True 

     End Function 

     Protected Overridable Sub OnPropertyChanged(ByVal strPropertyName As String, ByVal IsPrimaryProperty As Boolean) 
      Me.OnPropertyChanged(strPropertyName) 

     End Sub 

#End Region 

#Region " Navigation Events " 

     Protected Sub EnableNavigation() 
      'Keep from firing multiple onPropertyChanged events 
      If HasChanges = True Then 
       HasChanges = False 
      End If 

      GetEvent(Of DisableNavigationEvent).Publish(False) 

     End Sub 

     Protected Sub DisableNavigation() 
      'Keep from firing multiple onPropertyChanged events 
      If HasChanges = False Then 
       HasChanges = True 
      End If 

      GetEvent(Of DisableNavigationEvent).Publish(True) 

     End Sub 

#End Region 
    End Class 

End Namespace 

Answer 6

El WPF Application Framework (WAF) es de código abierto y contiene una clase base ViewModel (por implementando el patrón Model-View-ViewModel).

Answer 7

SoapBox Core es un marco MVVM (y MEF) de fuente abierta (LGPL) para la construcción de aplicaciones extensibles de MVVM. La jerarquía de clases incluye una clase base ViewModel (y una interfaz para el caso).